Body Arts and Science International (BASI) Pilates Practice Exam

The single leg circles performed on the Cadillac focus on the hamstrings and adductors due to the movement's design and purpose. During this exercise, one leg is extended while the other leg moves in a circular pattern. The engagement of the hamstrings is crucial as this muscle group assists in stabilizing the pelvis and controlling the leg's movement as it moves through the circular trajectory.

Additionally, the adductors play an important role in supporting the leg's motion and maintaining alignment of the body throughout the exercise. Together, these muscle groups work to ensure efficient movement patterns, promote stability, and enhance connectivity through the lower body, making them integral to the single leg circles on the Cadillac.

The other muscle groups mentioned in different choices do not accurately reflect the primary areas of focus in this specific exercise. For example, quads and glutes are more engaged during movements that require hip extension and flexion against resistance, while abs and back extensors are more involved in exercises that target the torso's stabilization rather than leg-specific movements.